My sister asked me to have a look at her notebook (a Medion Akoya P6612 with Windows Vista) because the CDROM drive wouldn’t work, and it was not even displayed in the Windows Explorer. I looked into the Device Manager and noticed that the CDROM device (TSSTCorp SN-S083a) was displayed with a small yellow exclamation mark besides its icon, and it said on the Properties page that the device could not be started and referred to Code 39. Reinstalling the drivers had no effect, but after I had a little chat with Big Blue G, I found a howto entry which suggested the following:

  1. Be logged in with an administrator account
  2. Open the Registry Editor (choose it from the Start Menu or press Win+R and type regedit)
  3. Navigate to HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Class\{4D36E965-E325-11CE-BFC1-08002BE10318}
  4. Then, in the right pane, delete all of the following keys:
    • UpperFilters
    • LowerFilters
    • UpperFilters.bak
    • LowerFilters.bak
  5. Restart your computer

This worked fine for us.